Canine fibroblast growth factor receptor 3 sequence is conserved across dogs of divergent skeletal size.
BACKGROUND
Fibroblast growth factor receptor 3 (FGFR3) is expressed in the growth plate of endochondral bones and serves as a negative regulator of linear bone elongation. Activating mutations severely limit bone growth, resulting in dwarfism, while inactivating mutations significantly enhance bone elongation and overall skeletal size. Domesticated dogs exhibit the greatest skeletal size diversity of any species and, given the regulatory role of FGFR3 on growth plate proliferation, we asked whether sequence differences in FGFR3 could account for some of the size differences.


METHODS
All exons, the promoter region, and 60 bp of the 3' flanking region of the canine FGFR3 gene were sequenced for nine different dog breeds representing a spectrum of skeletal size. The resultant sequences were compared to the reference Boxer genome sequence.


RESULTS
There was no variation in sequence for any FGFR3 exons, promoter region, or 3' flanking sequence across all breeds evaluated.


CONCLUSIONS
The results suggest that, regardless of domestication selection pressure to develop breeds having extreme differences in skeletal size, the FGFR3 gene is conserved. This implies a critical role for this gene in normal skeletal integrity and indicates that other genes account for size variability in dogs.
Smith
Logan B
LB
Department of Animal Science, University of California, Davis, CA, USA. lbsmith@ucdavis.edu
Bannasch
Danika L
DL
Young
Amy E
AE
Grossman
Deborah I
DI
Belanger
Janelle M
JM
Oberbauer
Anita M
AM
D024509:3' Flanking Region / Q000235:genetics; D000818:Animals; D000829:Animals, Domestic / Q000235:genetics; D001483:Base Sequence; D049628:Body Size; D001842:Bone and Bones; D001947:Breeding; D017124:Conserved Sequence; D004285:Dogs / Q000235:genetics*; D005091:Exons / Q000235:genetics; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics*; D016415:Sequence Alignment
D051498:Receptor, Fibroblast Growth Factor, Type 3